Variable wattage lamp socket



Feb. 14, 1956 RVJ STREGE 2,734,976

VARIABLE WATTAGE LAMP SOCKET Filed Aug. 7, 1953 INVENTOR. LESL/E E. STEEGE,

- ATTORNEYS.

United States Patent VARIABLE WATTAGE LAMP SOCKET Leslie R, J. Strege, Carlsbad, N. Mex. Application August 7, 1953, Serial No. 373,021

2 Claims. (Cl. 201-49) This invention relates to electric lamp sockets, and more particularly to an electric lamp socket of the type provided with means for varying the degree of energization of the lamp mounted therein.

The main object of the invention is to provide a novel and improved lamp socket having means for varying the current supplied to the lamp mounted in the socket and having indicating means to show the degree of energization of the lamp, the improved socket being simple in construction, being easy to adjust to the desired lamp wattage value, and providing a convenient and readily operable means for obtaining any desired degree of illumination from a lamp of given wattage rating.

A further object of the invention is to provide an improved variable wattage lamp socket, said socket being provided with manually operable means for varying the degree of energization of a lamp mounted therein, the improved socket being inexpensive to manufacture, being durable in construction, and being safe to use.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

Figure 1 is a top view of an upright lamp socket constructed in accordance with the present invention.

Figure 2 is a vertical cross sectional view taken on the line 22 of Figure 1.

Figure 3 is a front elevational view of the lamp socket of Figures 1 and 2.

Figure 4 is a vertical cross sectional detail view taken on the line 4-4 of Figure 2.

Figure 5 is a schematic wiring diagram of the socket of Figures 1 to 4.

Figure 6 is a partial schematic wiring diagram similar to Figure 5 but showing a modified form of the present invention.

Referring to the drawings, and more particularly to Figures 1 to 5, 11 generally designates an electric lamp socket according to the present invention. The lamp socket 11 comprises the upper and lower body segments 12 and 13 of insulating material, such as porcelain, Bakelite, or the like, said body segments being secured together and being keyed against relative rotation. The segments 12 and 13 may be secured together by the axial conductive bolt member 14 which secures the contact spring 15 to the center of the top portion of the segment 12 and which extends through a conductive terminal bar 16 disposed against the bottom surface of the body segment 13, said terminal bar 16 being secured to said bottom surface by a nut 17 threadedly engaged on the lower end of the conductive bolt 14. Threadedly engaged with the terminal bar 16 is the terminal screw 18 for electrically connecting one wire of the line cord to the contact spring 15.

Designated at 19 is the threaded metallic shell which is secured to the top end of the insulating body segment 12 by a machine screw 20 engaged through an inwardly extending lug 21 provided on the shell 19, the lug 21 being secured against the top flange of a conductive strap 22, whereby the screw 20 also fastens said strap 22 to the top 2,734,976 Patented Feb. 14, 1956 portion of insulating segment 12. The respective segments 12 and 13 are formed with mating semicircular recesses 23 and 2,4 which define a resultant circular recess when the segments 12 and 13 are secured together in the manner shown in Figure 2. Designated at 25 is a shaft member of insulating material which is rotatably mounted in a bore defined by mating semicircular grooves 26 and 27 in the marginal portions of the insulating body segments 12 and 13, said bore being directed at right angles to the axial bolt 14, whereby the shaft 25 s mounted for rotation around an axis normal to said bolt.

Secured in the wall 28 of segment 12 and arranged concentrically around the axis of shaft 25 are a plurality of resistance rods 29 of equal length and having their inner ends exposed in the recess 23. The outer ends of said rods are rigidly and electrically connected to an arcuate strap member 30 formed integrally with the contact strap 22, whereby the outer ends of the rods 29 are electrically connected to the shell 19 of the socket. The rods 29 have different resistances, the resistances of said rods gradually increasing in value from one side of the recess 23 to the other. The rods 29 each comprises a hardened matrix of heat resisting insulation material in which is embedded a quantity of comminuted metallic conducting material. For example, the matrix material may comprise powdered porcelain,Bal elite, plastic, marble, glass, or suitable clay material, together with bituminous binding material. The metallic particles may comprise comminuted silver, cop- P r. b a um num, ppe r m, yb e m, Zinc, or other suitable metallic particles having high electrical conductivity. The metallic particles are homogeneously distributed through the powdered matrix material and the o s a h n P ssu -m lded w th su abl h at e meat. 11 as bak ng o th like, h b he p e mixture is sintered to a rigid mass, the heat treatment being applied to the molds in which the powdered mixture is contained. The resistance of the rods may be regulated by varying the relative proportions of comminuted metal nd n ul t ng m r x m terialh m t x ma ial ha i h hea es tin p p t whereby the resultant rod element formed by the process above described is able to dissipate substantial quantities of heat without disintegrating.

The rods 29, as above explained, are arranged according to their resistivity in an arcuate row extending from one side of the recess 23 to the other. Secured to the inner end of the insulating shaft 25 is a resilient contact arm 31 which is successively engageable with the exposed inner ends of the rods 29 responsive to rotation of the shaft 25. The arm 31 is provided with an extension 32 diametrically aligned therewith and engaging an arcuate contact strap 33 disposed against the wall 34 of the recess 24 and connected to a terminal bar 35 provided at the bottom of the insulating body segment 13. A terminal screw 36 is threadedly engaged in the bar 35, whereby a wire of the line cord may be electrically connected to the switch arm 31.

The outer end of the shaft 25 is formed with the pointer knob 37. Designated at 38 is the outer metallic housing which is disposed around the components of the socket, a suitable insulating sleeve 39 being interposed between the housing 38 and said components. The housing 38 is provided adjacent the pointer knob 37 with the arcuately arranged indicating scale 40 provided with numerals designating the different positions of the shaft 25 wherein the switch arm 31 is engaged with the respective resistance rods 29, and also indicating an off position wherein the switch arm 31 is engaged with the surface of the wall 28, whereby the socket is open-circuited.

It will be readily apparent that a lamp mounted in the socket may be energized to a desired degree of brilliance by adjusting the pointer knob 37 to a corresponding position relative to the numbered scale 40. For example, where high brilliance is desired, the knob 37 will be adjusted to a position wherein the switch arm 31 engages the end of a rod 29 having relatively low resistance. Conversely, when the lamp is to be only dimly energized, the knob 37 is rotated to a position wherein the switch arm 31 engages the end of a resistance rod '29 having relatively high resistance.

Referring now to Figure 6 the resistance rods, shown at 29' may be formed of identical mixtures of cornminuted metal in heat resistant insulating material, wherein the resistance rods are progressively shortened in length from one side of the recess 23 to the other. Thus, the resistance rod 29' may be mounted in the wall 28 of the body segment 12 in any suitable manner, and the strap element 30 may be formed with successive steps secured to the outer ends of the respective resistance rods 29, the inner ends of the resistance rods being at equal distances from the axis defined by the bolt member 14. Thus, the resistance rods 29', may be cut from a sintered rod formed by a process as above described and comprising a substantially uniform mixture of cornminuted metal in heat resistant insulating material, the rods being cut to different lengths to provide the different desired values of resistance.

While certain specific embodiments of an improved variable wattage lamp socket have been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. In an electric lamp socket, an internally threaded metallic shell to receive the base of a lamp bulb, a body of insulating material, a contact member axially disposed in said body and having an end portion thereof extending into said shell for engagement with the center contact of the lamp bulb base, said body being formed with a recess at a right angle to said contact member, a plurality of rigid resistance rods having different resistances arcuately arranged in said body and having ends disposed in said recess, said rods being located at equal distances from an axis normal to said contact member located in said recess, a shaft member of insulating material mounted for rotation around said axis, a contact arm of conductive material secured to said shaft member and being selectively engageable with said first-named ends of said resistance rods, means electrically connecting the opposite ends of said rods to said shell, said rods each comprising a hardened matrix of heat resisting insulation material in which is embedded a quantity of cornminuted metallic conducting material, said shaft member projecting outside said body, and a pointer knob secured to the outer end of said shaft member.

2. In an electric lamp socket, an internally threaded metallic shell to receive the base of a lamp bulb, a body of insulating material, an axially disposed contact member having an end portion thereof extending into said shell for engagement with the center contact of the lamp bulb base, said body being formed with a recess, a plurality of rigid resistance rods having difierent resistances arcuately arranged in said body and having ends disposed in said recess, said rods being located at equal distances from an axis normal to said contact member, a shaft member of insulating material mounted for rotation around said axis, a contact arm of conductive material secured to said shaft member and being selectively engageable with said first-named ends of said resistance rods, means electrically connecting the opposite ends of said rods to said shell, said rods each comprising a hardened matrix of heat-resisting insulation material in which is embedded a quantity of cornminuted metallic conducting material, and an arcuate contact plate secured to said recess opposite said rods, a conductive element conductively secured to said contact arm and engaging said contact plate, respective terminals secured to the bottom of said body and being electrically connected to said axially disposed contact member and said contact plate, said shaft member projecting outside said body, and a pointer knob secured to the outer end of said shaft member.

References Cited in the file of this patent UNITED STATES PATENTS Weichelt Sept. 14, 1933 

